title: Effects of open burning of rice straw on concentrations of atmospheric polycyclic aromatic hydrocarbons in central Taiwan.
abstract: The sizes and concentrations of 21 atmospheric polycyclic aromatic hydrocarbons (PAHs) were measured at Jhu-Shan (a rural site) and Sin-Gang (a town site) in central Taiwan in October and December 2005. Air samples were collected using semi-volatile sampling trains (PS-1 sampler) over 16 days for rice-straw burning and nonburning periods. These samples were then analyzed using a gas chromatograph with a flame-ionization detector (GC/FID). Particle-size distributions in the particulate phase show a bimode, peaking at 0.32-0.56 microm and 3.2-5.6 microm at the two sites during the nonburning period. During the burning period, peaks also appeared at 0.32-0.56 microm and 3.2-5.6 microm at Jhu-Shan, with the accumulation mode (particle size between 0.1 and 3.2 microm) accounting for approximately 74.1% of total particle mass. The peaks at 0.18-0.32 microm and 1.8-3.2 microm at Shin-Gang had an accumulation mode accounting for approximately 70.1% of total particle mass. The mass median diameter (MMD) of 3.99-4.35 microm in the particulate phase suggested that rice-straw burning generated increased numbers of coarse particles. The concentrations of total PAHs (sum of 21 gases + particles) at the Jhu-Shan site (Sin-Gang site) were 522.9 +/- 111.4 ng/ml (572.0 +/- 91.0 ng/ml) and 330.1 +/- 17.0 ng/ml (or 427.5 +/- 108.0 ng/ml) during burning and nonburning periods, respectively, accounting for a roughly 58% (or 34%) increase in the concentrations of total PAHs due to rice-straw burning. On average, low-weight PAHs (about 87.0%) represent the largest proportion of total PAHs, followed by medium-weight PAHs (7.1%), and high-weight PAHs (5.9%). Combustion-related PAHs during burning periods were 1.54-2.57 times higher than those during nonburning periods. The results of principal component analysis (PCA)/absolute principal component scores (APCS) suggest that the primary pollution sources at the two sites are similar and include vehicle exhaust, coal/wood combustion, incense burning, and incineration emissions. Open burning of rice straw was estimated to contribute approximately 5.0-33.5% to the total atmospheric PAHs at the two sites.
authors.affiliation: Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan, Republic of China.
authors.forename: Kang-Shin
authors.initials: KS
authors.lastname: Chen
authors.forename: Hsin-Kai
authors.initials: HK
authors.lastname: Wang
authors.forename: Yen-Ping
authors.initials: YP
authors.lastname: Peng
authors.forename: Wen-Cheng
authors.initials: WC
authors.lastname: Wang
authors.forename: Chia-Hsiu
authors.initials: CH
authors.lastname: Chen
authors.forename: Chia-Hsiang
authors.initials: CH
authors.lastname: Lai
mesh_terms: D000383:Agriculture; D000395:Air Pollutants, Occupational / Q000032:analysis*; D004784:Environmental Monitoring; D012275:Oryza; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis*; D013624:Taiwan
chemical_list: D000395:Air Pollutants, Occupational; D052638:Particulate Matter; D011084:Polycyclic Aromatic Hydrocarbons